The present disclosure relates generally to measuring devices, and more particularly, to apparatus for measuring an angle of a guide wire relative to a bone.
A procedure regularly performed by orthopedic surgeons is the reduction of a hip fracture caused by trauma. The site of this type of fracture typically exists at the proximal portion of the femur below the head. In order to reduce a fracture of this type, an elongated lag screw is threadingly advanced over a guide wire into the shaft, neck, and head of the femur, and secured to a bone plate. Cortical screws are used to secure the bone plate to the femur distal to the fracture site. Tightening of the lag screw compresses the bone fragments together and facilitates healing of the femur. Many devices have been designed for this type of reduction including the devices disclosed in U.S. Pat. Nos. 4,438,762, 3,554,193, and 2,526,959, the disclosures of which are incorporated herein by reference in their entirety.
One step in the above-described procedure is to measure the angle of the guide wire relative to the femur to obtain an anteversion angle of the femur. In response to this measurement, an appropriately configured barrel (or fastener guide) may be selected for use in the lag screw assembly that is to be implanted in the femur. In particular, a barrel having a configuration that corresponds to the anteversion angle of the femur is selected, and thereafter joined with a lag screw to form a lag screw assembly that is then implanted over the guide wire in the femur.
Measurement of the guide wire relative to the femur may be made by a surgeon while the guide wire is located within the body of a patient, and in particular, positioned in the shaft, neck, and head of the femur of the patient. Alternatively, the measurement may be made while the guide wire is not located in the body of the patient, but rather is merely positioned on top of the patient's body in a position over the shaft, neck, and head of the femur.
One measurement apparatus that has been used to measure the angle of a guide wire relative to a femur to obtain an anteversion angle of the femur is a goniometer. Another measurement apparatus that has been used to measure such angle is a protractor.
It would be advantageous to design a measuring apparatus that facilitates precise measurement of the angle of a guide wire relative to a femur. It would be beneficial if such measuring apparatus was relatively easy to use. It would be additionally advantageous if such measuring apparatus could be used in association with an X-ray procedure to obtain highly accurate measurements. It would also be beneficial if such measuring device would facilitate advancement of a guide wire into the femur at a predetermined angle.
What is needed therefore is an apparatus for measuring an angle of a guide wire relative to a bone such as a femur that facilitates precise measurement. What is also needed is such a measuring apparatus that is relatively easy to use. What is further needed is an apparatus for measuring an angle of a guide wire relative to a bone that could be used in association with an X-ray procedure to obtain highly accurate measurements. What is additionally needed is an apparatus for measuring an angle of a guide wire relative to a femur that facilitates advancement of a guide wire into the femur at a predetermined angle.